The present invention relates to image processing, and more particularly to a novel approach for using monocular cues acquired from a single two dimensional image to improve depth perception.
Traditionally, the ability to perceive depth from two-dimensional images has been accomplished by binocular methods. Binocular methods are discussed in D. Marr and T. Poggio, "Cooperative Computation of Stereo Disparity," Science, vol. 194, pp. 283-287 (1976) and S. Barnard and M. Fischler, "Computational Stereo," Computing Surveys, vol. 14, no. 4, pp. 553-572 (December, 1982). Binocular depth cues, such as disparity, required multiple images (i.e., a stereo pair of images) and matching of corresponding points, which is a computationally complex and error-prone task. More recently, researchers have developed monocular approaches by comparing images using differing apertures, as discussed in A. Pentland, "a New Sense For Depth of Field," IEEE Transactions on Pattern Analysis and Machine Intelligence," vol. 9, no. 4 (July, 1987) and G. Surya and M. Subbarao, "Depth From Defocus By Changing Camera Aperture: a Spatial Domain Approach," Proceedings of IEEE Transactions on Pattern Analysis and Machine Intelligence, pp. 61-67 (1993). Monocular depth cues such as blur, have been used to perceive depth. In these approaches, point matching was not required, but multiple images were required for depth perception.
Researchers have begun looking at integration of binocular and monocular cues. Several researchers have studied the result of combining cues to perceive depth from two dimensional images. Examples of this type of work include N. Gershon, "Visualizing 3D PET Images," IEEE Computer Graphics and Applications, vol. 11, no. 3, pp. 11-13 (1991), and S. Marapane and M. Trivedi, "An Active Vision System For Depth Extraction using Multi-Primitive Hierarchical Stereo Analysis and Multiple Depth Cues," SPIE, vol. 1956, pp. 250-262 (1993).
Others have studied how these different cues interact to create a depth effect. In these studies, binocular cues have been considered important and large contributors to depth perception in two dimensional images. However, as noted above, multiple images are required to extract these cues. Examples of this type of work include R. Surdick et al., "Relevant Cues For the Visual Perception of Depth: Is Where You See It Where It Is?," Proceedings on the 38th Meeting On Human Factors and Ergonomics Society, pp. 1305-1309 (1994), R. Srinivasan et al., "Computing Surface Information From Monocular and Binocular Cues For Vision Applications," Proceedings of the 27th Conference of Decision and Control, pp. 1085-1089 (1988), and S. Das et al., "Dynamic Integration Of Visual Cues For Position Estimation," SPIE, vol. 1382, pp. 341-352 (1990).
Therefore, a need exists for a method for improving depth perception using only monocular cues acquired from a single image.